Marine Creepers are a passive mob found in oceans, swimming around squids. They seldom interact with the player, and normally ignore them. They are a unique mob type that does not explode and can carry and use items.
Marine Creepers will often be spotted "herding" squids into larger bodies of water so they can swim. Marine Creepers are somewhat like the creeper equivilant of dolphins, and can be observed flying several feet into the air with squids, then crashing back under. They flee from Players and herd squids away when another land-mob comes by. They are particularly faster than squids.
Marine Creepers live in Ocean biomes, having a 31.67% chance of spawning in a 3x3x3 block volume of water.